Rotating ditch and method



Oct. 14, 1969 E. A. MORI HOTATING DITCH AND METHOD 3 Sheets-Sheet l N..MNHN

IN VE NTOR. fen/557A. Maw

Oct. 14, 1969 E. A. MORI ROTATING BITCH AND MNH@ Filed Dec. 22, 1967 0 uM wfw f m beets-Sheet .C5

Oct. 14, 1969 E. A. MORI ROTATING BITCH AND METHOD Filed DGO. 22 1967United States Patent O 3,472,324 ROTATING DITCH AND METHOD Ernest A.Mori, Glenshaw, Pa., assignor to Gulf Research & Development Company,Pittsburgh, Pa., a corporation of Delaware Filed Dec. 22, 1967, Ser. No.692,736

Int. Cl. E21b 21/00 U.S. Cl. 175-66 12 Claims ABSTRACT OF THE DISCLOSUREThe invention comprises a ditch or return line for use in rotary methodsof drilling wells in the earth with means to rotate the ditch about itsown axis, and with various adjusting means to adjust height and angle,and to permit use of various size diameter ditches.

This invention relates to the art of drilling wells in the earth by therotary method utilizing fluid circulation. As is known, in drillingwells to hydrocarbon bearing deposits, a long string of pipe carrying adrill bit on its lower end is employed. Fluid, known as drilling mud, ispumped downwardly through the drill pipe and out the drill bit, and isthen returned to the surface in the annulas between the hole drilled andthe drill pipe. The drilling mud is reconditioned on the surface andrecirculated through the well. The drilling mud serves to carry cuttingsup out of the well, constrain pressures that are encountered in theborehole, cool the bit, and other purposes well known to those skilledin this art.

The invention is directed to a portion of the uid handling apparatus foruse in the rotary method of drilling above described, particularly, theditch or return line which is positioned between the upper end of thesurface pipe and the mud reconditioning equipment. Surface pipe is largetube or casing which denes the outside of the annulus between theborehole and the drill pipe through the upper end of the well up to andslightly above the surface. The surface pipe is provided with a flownipple nears its upper end which extends out to one side away from theaxis of the well and through which the return mud iiows. A return lineor ditch comprising flexible tubing, a length of pipe, a trough, orother means is provided between the flow nipple and the first piece ofmud reconditioning equipment. In place of the conventional ditch, thepresent invention provides a straight length of pipe which is rotatablysealed to the outer end of the flow nipple, with means to rotate thepipe about its own axis to thereby achieve advantages over and solveproblems present in prior known return lines.

The rst piece of mud reconditioning equipment to which the outflow fromthe conventional ditch or the rotating ditch of the present invention isfed is a device known as a shale shaker. The shale shaker comprises ascreen and means to vibrate the screen so that cuttings in the mud willbe separated out. The cuttings, depending on their particular nature andthe combination of their nature with the nature of the particular mud,may form clumps or slugs of material which can clog the ditch, which canbe detrimental to normal operation of the shale shaker, which can causebacking up of fluid in the ditch, and which can cause overflow of mudfrom the ditch and/ or from the top of the surface pipe.

The clumping and clogging problem becomes intensied in the so-calledhydraulic or jet drilling method, described in U.S. Patent No.3,375,887, to Goodwin et al., Ser. No. 660,065, tiled Aug. l1, 1967, andassigned to the same assignee as the present invention. In said jetdrilling method, a plurality of high velocity streams of abrasive ladendrilling mud are utilized in drilling the well. The abrasive used may besand, steel or iron particles such as shot, or other relatively smallparticles of relatively hard material. In jet drilling, signiiicantconcentrations of the abrasive are included in the mud, and theabrasives themselves or in combination with the cuttings may increasethe frequency of occurrence of clumps forming in the mud in the ditch.The mud used in jet drilling must be more viscous than the mud used inconventional rotary drilling to enable it to suspend or carry theabrasive particles. The higher viscosity mud may further increase thefrequency of formationl of clumps or the like in the return line.

In conventional usage, the return line has a downward inclination fromthe surface pipe to the shale shaker. A possible solution is that byincreasing the angle of inclination, the jet drilling mud may flowsatisfactorily through a conventional ditch because of the increasedgravitational pull. That solution is not practical because it isdesirable, for reasons of safety, to keep the mud handling equipment asfar from the well as possi-ble. With the rotating ditch of the presentinvention invention, the angle of inclination can be very close tohorizontal, angles on the order of 3 have been successfully used, tothereby position the shale shaker and other mud handling equipment at asafe distance from the wellhead without special equipment to increasethe height of the flow nipple above the shale shaker.

The rotating ditch of the present invention comprises a length ofstraight pipe, and means to rotate the pipe. Actual use has shown thatthe rotating ditch of this invention will maintain a clump-free andsteady llow of heavy, viscous, abrasiveladen jet drilling mudtherethrough. Conventional return lines have failed to operatesuccesfully with jet drilling mud because of the relatively highviscosity of the mud itself, and the relatively heavy weight of the mudwith the abrasive therein.

The return line of the invention requires no balies, paddles, screws, orother extraneous agitation means inside it. By not providing suchagitation means, the cost of fabricating the invention is kept to aminimum. Further, such bales, screws, paddles, or the like agitationmeans would in fact be a disadvantage in the rotating ditch of theinvention because it is desirable to always have as little mud in theditch as posible. Any internal agitation means must hold some additionalmud in the ditch, requiring that the amount of mud in the overall mudsystem be increased. The additional mud makes the ditch heavier and morediiicult to support and rotate. In jet drilling additional mud requiresadditional abrasive to maintain constant abrasive concentration furtherincreasing the desirability of always having at little mud in the ditchas possible. Abrasive in the ditch is not in use and the abrasive is arelatively expensive material. Still further, any such internalagitation means would form regions of mud movement of differing speeds,and settling of abrasive in the slower moving mud would form regions ofhigh abrasive concentration in the ditch which would disrupt or destroythe abrasive concentration of the system. Jet drilling produces cuttingswhich are generally larger than the cutting produced in conventionalrotary drilling, and the larger, heavier cuttings further increase thetendency of a stationary ditch to form clumps or plug or overflow. Thus,the rotating ditch of the invention avoids all of the above problems,while permitting a relatively low cost of fabrication.

let drilling mud will suspend the abrasive particles at cutting speedvelocities of the mud and when the mud is not moving. However, when themud :is moving slowly, as in a return line, the abrasive particles willsettle out. Thus, in a stationary ditch, the abrasive concentrationbalance of the system is impaired by the abrasive settling at the bottomof the ditch. The abrasive concentrated at the bottom of a conventionalditch adds to the problems of ditch plugging, overfiowing, backing up,and the like, described above. The rotating ditch of the inventionovercomes the settling problem by not permitting abrasive to build up atthe bottom of the return line due to the rotional motion, which causesuniform mixing of the abrasive, and other solids, cuttings, in the mudin the return line. An additional advantage of the invention is that therotational motion reduces friction and thereby aids mud `flow down thereturn line.

The rotating ditch of the invention is particularly advantageous in bothconventional and jet drilling rigs where a soft or easily drilledformation is encountered. Such formations, soft shale for example,produce relatively large quantities of cuttings in relatively shortperiods of time, which cuttings, if not smoothly delivered by therotating ditch of the invention, can seriously foul the mud handlingequipment.

Other advantages of the invention will be pointed out or will becomeevident in the following detailed description and claims, and in theaccompanying drawing also forming a part of the disclosure, in which:FIG. 1 is a partial elevational view of a drilling installationutilizing the rotating ditch of the invention; FIG. 2 is an enlargedview of a portion of the showing of FIG. l; FIG. 3 is a top plan View ofthe means to rotate the ditch; and FIG. 4 is a front end view of theshowing of FIG. 3.

Referring now in detail to the drawing, designates the sub-structure ofa well drilling derrick, 12 designates the rotating ditch of theinvention, and 14 designates the mud handling equipment. Sub-structure10 comprises a plurality of support members 16, the exact configurationof which are unimportant. The derrick floor 18 carries a rotary table 20in which is fitted the drill pipe 24. Conventional means, known as aKelly, not shown, are interposed between rotary table 20 and drill pipe24 to turn the drill pipe about its axis for drilling. It will beunderstood by those skilled in this art, that FIG. 1 is somewhatdiagrammatic in that many usually provided portions of the derrick arenot shown.

The derrick, not shown, which is carried by the substructure 10, isdisposed over the well being drilled, the outside of which is defined bysurface pipe 22. Surface pipe 22 is provided with a flow nipple 26,which comprises a short length of pipe welded into a suitably formedopening in the wall of surface pipe 22. The rotating ditch of theinvention comprises a flow pipe 28, the upper end of which is joined toflow nipple 26 by a rotating iluid tight seal connecting member 30,which is known as a Chiksan joint, made by The Chiksan Co. of Brea,Calif. The high or Well end of pipe 28 is supported on an idler rollersupport assembly 32. The low or mud tank end of pipe 28 is carried by apower drive and supporting assembly 34. Pipe 28 may have a diameter inthe range of about 8 inches to about 16 inches, with a diameter of 12inches being suitable for most applications.

Mud handling equipment 14 comprises a shale shaker 36, of the typedescribed above, which is positioned over a mud tank 38, shown in endview in FIG. l. It will be understood that various other additionalpieces of equipment such as pumps, stirrers, and the like are associatedwith mud handling equipment 14, but that they need not be shown orexplained further here.

Referring to FIG. 2, there is shown the apparatus of the invention indetail. Idler assembly 32 comprises a bottom support 40, which comprisesa base made up of four pieces of angle iron 42, each of which disposedwith one fiange facing upwardly and one flange resting on the earth orother surface supporting the ditch and disposed in* wardly. The pieces42 are cut on a 45 angle and are joined together by any suitable meanssuch as welding. In each of the corners within the base formed by angleirons 42, is an upright member 44 which comprises a length of pipe. Thefour uprights 44 are joined together, intermediate their ends, byangularly disposed struts 46, one strut 46 being provided between eachtwo uprights 44. The upper end of support 40 is joined together bysuitable top members 48 which may comprise rod or pipe. Each upright 44is provided with a row of openings 50, which are used to adjust theheight of the upper member, as will appear more clearly below.

Adjustably mounted in support 40 is an upper idler assembly 52 made upof four uprights 54 formed of pipe having a diameter that will snuglyand slidingly fit within uprights `44 of support 40. In spaced relationto its lower end each upright 54 is formed with three closely spacedopenings 56. The space covered by the three openings 56 is equal to orless than the space between two openings 50 in uprights 44, whereby fineand coarse adjustment of the height of the idler rollers is provided,coarse adjustment on holes 50, and fine adjustment on holes 56 incooperation with one set of holes 50. A locking nut and bolt assembly 58is provided in each corner to pass through the openings 50 and 56. Theuprights 54 are joined together by struts `60 welded or otherwise joinedto them in spaced relation to their upper ends. The upper ends ofuprights 54 are joined together by lengths of angle iron 62 and form astructure similar to the base formed by angle irons 42 described below.A roller supporting strap 64 is welded or otherwise joined to a pair ofthe angle irons 62. Referring to FIG. 2, a pair of heavy duty casters66, or other suitable anti-friction roller means, are mounted on strap64 by means of nut and bolt assemblies, not shown, which cooperates withsuitable slots in the strap 64. Thus, 4the casters 66 may be adjustedtoward and away from each other to accommodate various sizes of pipe tobe used as the ditch.

Referring to FIG. 2, drive assembly 34 comprises a lower supportidentical to support 40 in idler assembly 32. The provision of identicalsupports for the drive assernbly 34 and the idler assembly 32 gives theinvention the advantage of interchangeability of parts.

Drive assembly 34 comprises an upper assembly 70 which comprises fouruprights 72 similar in structure and operation to the uprights 54 ofupper assembly 52. The lower ends of the uprights 72 are provided withopenings 56d and nut and bolt assemblies 58a similar to the parts 56 and58 described above. The upper ends of the uprights 72 are joinedtogether by four pieces of angle irons 74 to strengthen the structure. Avertically disposed angle iron 76 secured to the upper end of eachupright 72 and extends thereabove. The upper end of the four angle irons76 support a frame made up of four horizontally disposed angle irons 78formed with mitered corners, see FIGS. 3 and 4. The angle irons 74extend only between the flanges of the vertically disposed angle irons76 so that the inside corner of each angle iron 76 is disposed directlyagainst the upper end of the uprights 72 and is welded in place thereon.A strap 80 is disposed across and is suitably secured to the frameformed by the angle irons 78. A pair of ditch supporting casters orrollers 82 are adjustably supported on strap 80 for movement thereontowards and awayl from each other by means of slots 84 formed in thestrap. Nut and bolt assemblies 86 secure the rollers 82 to the strap 80.Thus, the two ditch supporting rollers 82 can be moved closer togetheror further apart to accommodate various diameters of rotating ditches 28which may be used depending on the demands of the particularinstallation.

Means are provided to drive the rotating ditch 28, and to provide athird roller above the first two rollers 82 to` provide a three-pointcontact against the ditch, while at the same time maintainingsufi'icient flexibility to permit the use of different sizes of pipe forthe ditch. To thisend, a motor and idler supporting sub-assembly 88 isadjustably mounted on a pair of the vertical angle irons 76.Sub-assembly 88 is supported on a short, vertically disposed angle ion90 and a long, vertically disposed angle iron 92, each provided with aplurality of openings which may be brought in registry with any ofseveral similarly spaced openings formed in a contact-` ing flange oftwo of the angle irons 76 and secured thereto by suitable nut and boltassemblies 94. Thus, the entire motor and idler sub-assembly 88 may bemoved vertically with respect to upper assembly 70, and secured atvarious heights thereon.

A pair of relatively large motor supporting angle irons 96 extendoutwardly, one from the upper end of short angle iron 90 and the otherfrom mediately the ends of long angle iron 92. The horizontal iianges ofthe two angle irons 96 carry a motor base supporting underplate 98, onwhich is mounted a commercial universal motor mount 100. The outer endsof the large angle iron 96 are joined together and the structurerigidified by an angle iron 102, and the motor supporting structurefurther strengthened by a pair of angularly disposed struts 104 whichmay be formed of angle iron, or rod, or the like. The inner ends of thelarge angle irons 96 are joined together by an angle iron 106. Mountedon the top of universal mount 100 for adjustment to the left and right(looking at FIG. 4) is a bottom plate 108, which carries a pair of frontend uprights 110, and a rear yoke 112. An upper swinging plate 114 ismounted on uprights 110 and yoke 112 by means of a pair of front endjournal members 116. A pin 118 passes through suitably formed openingsin uprights 110 and journal members 116 to rotatably mount plate 114about the axis of pin 118. A threaded member 120 has its lower endrotatably mounted within yoke 112 and its upper end provided with doublesuitable nuts and washers which are received within a cutout in the rearend of swinging plate 114. A gear-motor 122 is secured to swinging plate114 by suitable means not shown, and comprises an output drive pinion124. It will be understood that gearmotor 122 comprises suitable speedcontrols, on-o controls, and an electrical supply cable, allconventional and not shown. Thus, the angular position of output pinion124 may be adjusted so that its axis is parallel to the axis of rotatingditch 28 by means of changing the position of swinging plate 114 onthreaded member 120. The angle of the ditch is controlled by theoverall, adjustable, heights of the idler and drive assemblies 32 and 34with respect to each other.

Subassembly 88 further comprises an angle iron 126 which extendsupwardly from angle iron 106 to a height equal that of long angle iron92. The upper ends of angle irons 92 and 126 are joined together by anangle iron 128. A roller supporting plate 130 is joined to the up--wardly extending frame formed by angle irons 92, 126 and 128, andcarries an upper ditch guiding roller assembly 132.

To complete the drive chain, a split clamp ring 134 is provided. The twohalves of the clamp ring are secured tightly to the rotating ditch at aposition thereon close to the plane of pinion 124. Spaces are providedbetween the halves of the clamp ring 134 so that the tightening nut andbolt assemblies 135 will bridge the spaces to assure that the clamp ringtightly grasps the rotating ditch. A drive sprocket 136 is slipped overthe ditch 28 and secured to the clamp ring 134 by bolts 138. A suitabledrive chain 140 interconnects pinion 124 and sprocket 136.

If it should be desired to change the size of the return line 28 becauseof larger or smaller uid flow demands, the only changes required arethat a suitably sized clamp and sprocket 134 and 136 be provided, thetwo rollers 82 moved to provide a larger or smaller space between them,the subassembly 88 slid up or down to bring the roller 132 in contactwith the ditch, the length of the chain 140 corrected, and theconversion is completed.

While the invention has Ibeen described in detail above, it is to beunderstood that this detailed description is by way of example only, andthe protection granted is to be limited only within the spirit of theinvention and the scope of the following claims.

Iclaim:

1. In a rotary method of drilling wells in the earth comprising the useof a fluid which circulates through the well from the surface to thebottom of the well, returns to the surface and is delivered toreconditioning equipment through a return line extending from the top ofthe well to surface drilling fluid handling and recondi tioningequipment, the improvement comprising rotating the return line about itsown axis.

2. The method of claim 1, and disposing the rotating return line at anangle of about 3 olf horizontal with the high end of the return line atthe well.

3. In apparatus for drilling wells by the rotary method, the combinationcomprising a return line extending from the well surface pipe todrilling lluid handling equipment, a flow nipple extending from saidsurface pipe, rotary sealing means to connect one end of said returnline to said llow nipple in fluid liow communication therewith, andmeans to support said return line and to rotate said return line aboutits own axis.

4. The combination of claim 3, said return line cornprislng a straightlength of about plain pipe having a diameter in the range of about 8inches to about 16 inches.

5. The combination of claim 3, said support means comprising an idlerassembly and a drive assembly, said idler assembly and said driveassembly comprising a similar bottom support, and said bottom supportcomprising a plurality of tubular uprights adapted to adjustably receivethe upright portions of a cooperating upper member.

6. The combination of claim 5, said idler assembly comprising an uppermember having upright portions receivable within the tubular uprightportions of said bottorn support, said idler assembly comprising a pairof rollers on the top thereof and means to change the distance betweensaid rollers, said adjusting means between said nesting uprights of saidbottom support and said upper member comprising a plurality of openingsspaced apart vertically on Said tubular uprights of said bottom supportby a lirst distance, and a second set of openings spaced apartvertically on said uprights of said upper member vwith the overalldistance between the highest and the lowest of said openings in saiduprights of said upper member being lsubstantially equal to said iirstdistance.

7. The combination of claim 3, said return line rotating meanscomprising a bottom support and an upper member, a pair of rollers onthe top of said upper member adapted to rotatingly support said returnline and means to change the distance between said rollers, a drive andupper idler sub-assembly, means to adjustably mount said drive and upperidler sub-assembly on said upper member of said drive assembly, saidsub-assembly comprising vertical portions adapted to be secured atvarying heights with respect to vertical portions of said upper member,support means extending laterally from said vertical portions of saidsubassembly to the side thereof opposite the side on which said returnline is disposed, drive means, means to mount said drive means on saidsupport portions of said sub-assembly, said drive means comprising apower pinion, said drive means mounting means comprising means todispose said power drive pinion in a plane substantially perpendicularto the axis of said return line, a sprocket, means to mount saidsprocket on said return line, and power transmission meansinterconnecting said pinion and said sprocket.

8. The combination of claim 7, said means to mount said sprocket on saidreturn line comprising a clamp, said return line clamp comprising a pairof semicircular clamp members, means to clamp said clamp members to saidreturn line, and means to secure said sprocket to said clamp.

I9. The combination of claim 7, said drive means comprising a gearmotor, said means to mount said gear motor with said pinion thereof in aplane substantially perpendicular to the axis of said return linecomprising a bottom plate, a top plate swingably mounted on said bottomplate with said gear motor thereon, and means to dispose said top plateat an adjustable angle with respect to said bottom plate.

10. The combination of claim 9, said bottom plate comprising a pair ofuprights and a yoke, said top plate comprising a pair or journal membersdisposed in juxtaposition to said bottom plate uprights respectively, apin rotatably interconnecting said uprights and said journal members, athreaded member swingably received within said yoke of said bottomplate, said upper plate being formed with a cut-out adapted to receivethe upper end of said threaded member, and nut and bolt means on saidthreaded member adapted to move the notched end of said upper plate withrespect to said threaded member around said pin member.

11. The combination of claim 7, said bottom support of said driveassembly comprising a plurality of tubular upright portions, said uppermember of said drive assembly comprising upright portions receivablewithin said tubular upright portions of said bottom support, heightadjusting means between Said nesting portions of said bottom support andsaid portions of said upper member received therein, said adjustingmeans comprising a first set of vertically spaced openings on saidtubular uprights of said bottom support, a second set of verticallyspaced openings on said uprights of said upper member, and the distancebetween the highest and the lowest of said second set of openings beingsubstantially equal to the distance between any two adjacent openings ofsaid rst set of openings.

12. The combination of claim 7, a third roller on said vertical portionsof said sub-assembly, whereby by adjustment of said sub-assembly on saidupper member, said third roller is brought into Contact with said returnline adjacent the top thereof to provide a three-point contact betweensaid rollers and said return line to hold said return line in positionon said rollers.

References Cited UNITED STATES PATENTS 2,302,112 11/1942 Eddy 209-113 X2,576,283 11/1951 Chaney 175-66 2,657,016 10/1953 Grable 175-206 X3,135,685 `6/1964 Tanner 175-206 X 3,292,384 12/1966 Rubin 209-113 XNILE C. BYERS, JR., Primary Examiner U.S. Cl. X.R.

